(a) Field of the Invention
The present invention relates to a driving apparatus for a display device and a display device including the same, as well as a method of driving the display device. More particularly, the present invention relates to a driving apparatus that reduces power consumption by increasing a driving voltage only at a temperature that requires low temperature driving, and a display device including the same and method of driving the display device.
(b) Description of the Related Art
In recent years, flat panel displays such as organic light emitting diode (“OLED”) displays, plasma display panels (“PDPs”), and liquid crystal displays (“LCDs”) have been widely developed for use instead of heavy and large cathode ray tubes (“CRTs”).
The PDP devices display characters or images using plasma generated by a gas discharge. The OLED display devices display characters or images by applying an electric field to specific light emitting organic or high molecule materials. The LCD devices display images by applying an electric field to a liquid crystal layer disposed between two panels and regulating the strength of the electric field to adjust transmittance of light passing through the liquid crystal layer.
Among the flat panel displays, as examples, the LCD and the OLED devices each include a panel assembly provided with pixels including switching elements and display signal lines, a gate driver providing a gate signal for gate lines of the display signal lines to turn the switching elements on and off, a gate signal generator for generating a gate signal to supply the gate signal to the gate driver, and a driving voltage generator for generating a driving voltage required for generating the gate signal.
Particularly, the driving voltage generator includes a DC/DC converter for generating a driving voltage and a feedback unit receiving the generated driving voltage as a feedback signal.
The gate driver may be integrated in the panel assembly that is formed together with the switching elements. The gate driver includes a plurality of transistors. The plurality of transistors are semiconductor devices, which have characteristics that change according to temperature. In the display devices such as a liquid crystal display, low temperature driving in which operation of the liquid crystal display occurs at sub-zero temperatures becomes a problem. When the ambient temperature decreases, the threshold voltage of the transistors increases. In this case, the switching elements of the pixels are controlled by increasing the amplitude of the driving voltage generated from the DC/DC converter and increasing the absolute value of a gate signal generated from the gate signal driver.
The feedback unit includes a plurality of diodes connected in series, and the feedback unit adjusts the amplitude of the driving voltage according to temperature by feeding back the driving voltage from the DC/DC converter and providing the feedback driving voltage to the DC/DC converter via the diodes. However, the diodes are semiconductor devices as well, so their threshold voltage also changes according to temperature, and the amplitude of the driving voltage is adjusted by sensing this change as well.
However, when the temperature changes and the threshold voltage of the diodes also gradually changes, as discussed above, the threshold voltage increases even at a temperature above zero at which no low temperature driving is required, thereby increasing power consumption. In order to make up for such a problem of unnecessary power consumption when no low temperature driving is required, the number of diodes can be reduced. However, it may then be impossible to obtain a driving voltage required for low temperature driving when the number of diodes are reduced in the feedback unit.
Accordingly, a technical problem to be solved by the present invention is to provide a driving apparatus for a display device that can obtain a driving voltage required for low temperature driving while reducing power consumption, and a display device including the same.